A touch panel optical waveguide which obviates the need for positioning light receiving cores of the optical waveguide with respect to light emitting cores of the optical waveguide, and to provide a touch panel employing the optical waveguide. A projection (5) is provided in one of longitudinally opposite end portions of an elongated optical waveguide (A), and a recess (6) to be engaged with the projection (5) is provided in the other end portion of the elongated optical waveguide (A). By engaging the projection (5) with the recess (6), distal ends of light emitting cores (3) are automatically and accurately opposed to distal ends of light receiving cores (3) with the intervention of a display screen of a touch panel.